The main objective of this network application, as established by the RFA-New Interventions for Menopausal Symptoms (UO1)-is to accelerate the identification of effective remedies to relieve hot flashes. We have created a network of scientists who are highly knowledgeable about the menopausal transition and experienced in the conduct of women's health trials to fulfill this objective: The Menopausal Symptoms Initiative-Finding Lasting Answers to Sweats and Hot Flashes (MSI-FLASH). Our Data Coordinating Center will be led jointly by Andrea LaCroix and Garnet Anderson who have served together as Co-Principal Investigators of the Women's Health Initiative Clinical Coordinating Center for over a decade. The MSI- FLASH network has five clinical sites: Boston (PIs: Lee Cohen and Hadine Joffe), Indianapolis (PI: Janet Carpenter), Oakland (PIs: Barbara Sternfeld and Bette Caan), Philadelphia (PI: Ellen Freeman) and Seattle (PIs: Katherine Newton and Susan Reed). This multidisciplinary investigator group proposes five randomized controlled trials testing a range of behavioral, hormonal and non-hormonal pharmacologic interventions to treat hot flashes. The specific trial proposed by our Boston site will test the relative efficacy of low-dose estrogen therapy and the selective serotonin-reuptake inhibitor (SSRI) paroxetine for the treatment of hot flashes. This randomized placebo-controlled double-blind trial includes: 1) a head-to-head comparison of the efficacy of estrogen and paroxetine; 2) a comparison of each intervention with placebo; 3) an assessment of potential modulating effects of co-occurring menopausal symptoms of sleep disturbance, depression, and anxiety; and 4) an examination of the complex inter-relationships between hot flashes and other menopausal symptoms using both subjective and objective measurements of hot flashes and sleep patterns. The Boston clinical site investigators have extensive experience with both hormonal and non-hormonal pharmacologic trials, as well as with behavioral interventions, and are well-positioned to collaborate on trials proposed by other MSI-FLASH clinical site investigators. Results of our proposed clinical trial will advance the treatment of hot flashes by establishing the relative efficacy of first-line pharmacologic treatments and determining whether specific clinical characteristics modulate response to treatment.